"In Israel, it's hard to enter a supermarket or a bus station without passing through a metal detector. Britain responded to years of politically motivated bombing campaigns by Northern Ireland's paramilitaries by installing closed-circuit television cameras on every street corner. Today, the country has a CCTV camera for every 11 people.

Armed guards, police security patrols, safe rooms and sophisticated surveillance systems are now routine measures deployed by Jewish synagogues, schools and restaurants in France following a wave of anti-Semitic attacks that began decades ago.

Hungarian synagogues are linked by a centralized, rapid "early warning system" that alerts Jewish prayer houses in the rest of the eastern European nation of an attack.

Japan removed trash cans from subway stations and local parks following a Sarin gas attack by one of its citizens that killed 13 people and sickened thousands. Its security officials concluded they were a good place to hide incendiary devices.

Australia made sweeping gun control measures after a man killed 35 people with a semi-automatic weapon in a popular tourist area in 1996. The country banned rapid-fire guns and offered to buy prohibited firearms. Research suggests it's worked."